According to an official statement on Ryujinx’s Discord server, developer gdkchan was contacted by Nintendo and they were offered an agreement to stop working on the emulator project, and while the agreement wasn’t confirmed yet, the organization has been entirely removed.
There are only so many programmers who are good enough to create an emulator, and a lot of them are already doing other projects. The Switch is also a very complicated system, and it needs a small team to pull it off.